FIG. 66. Steps in the development of the yellow dogtooth violet (Erythro- 

 nium americanum) from the seed to the seventh year 



The diagram for the most part explains itself. The student should note that the 

 seed begins to germinate late in the first year, becoming a seedling early in the 

 second year. The cotyledon of the seedling accomplishes enough food making by 

 photosynthesis to enable the plant to form a small bulb. This is maintained with- 

 out much increase in size throughout the third year. During the fourth, the fifth, 

 and the sixth years the increasing size of the leaf permits the production of larger 

 and larger bulbs, until in the seventh year enough plant food has been accumu- 

 lated in the bulb to send up two leaves and produce a flower and fruit. The third 

 bulb may repeat itself indefinitely, not gaining much in depth. In this case the 

 interval between germination and flowering would be more than six years (the 

 time indicated in the diagram). Each well-developed bulb may (in this species) 

 form runners, rh, which bring about vegetative reproduction, the small bulb at the 

 end of each growing into a new plant. Modified after Blodgett 



